/*基本css*/
* {
    margin: 0;
    padding: 0;
    /*设置内减模式，盒子不会被改变大小*/
    box-sizing: border-box;
}

html,
body {
    height: 100%;
    width: 100%;
}

body {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

h1 {
    padding-top: 15px;
}

.main_body {
    flex: 1;
    width: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

form {
    width: 40%;
    padding: 10px;
    border-radius: 5px;
    box-shadow: 0 0 50px 10px #5d5d65;
}

.form-group {
    margin-bottom: 15px;
}

.form-group:last-child {
    margin-bottom: 8px;
}

#mainForm .text-center .btn {
    width: 70px;
    height: 35px;
}

.form-group select {
    width: 80px;
    border-radius: 5px;
    margin-left: 10px;
}

.btn_return {
    margin-top: 20px;
}

.btn-info {
    width: 80px;
    height: 45px;
}